Microblogging website Twitter is all set to tweet its way into billion-dollar revenues in the next two years, apparently thanks to its growing mobile ad revenue.

Beancounters at market research firm eMarketer now estimate that Twitter will earn $582.8m in global ad revenue this year, $950m next year and then break the billion-dollar barrier with $1.33bn in 2015.

eMarketer reckons the website - which, we're told, has 200 million users tweeting 400 million messages a day - will get more than half of its revenue from mobile advertising in 2015 as opposed to virtually no mobe ad cash in 2011.

"The upward revision comes as advertisers have shown more interest in spending money on mobile advertisements on Twitter, and as recent audience figures from multiple research sources analysed by eMarketer have suggested Twitter's reach is improving," the firm said.

The increased push to mobile by competitors including Google and Facebook has actually helped Twitter, because it has pushed advertisers' money over to mobe ads. eMarketer also believes that the "native" nature of Twitter ads, such as sponsored tweets, has allowed the microblogging site to integrate ads across devices and build its business quickly.

"eMarketer estimates Twitter will earn $308.9 million in mobile ad revenue in 2013—which is more than the company earned in total, from any ad type, in 2012, when it made $138.4 million from mobile ads," the firm said.

The beancounters said they came up with their forecast by analysing estimates "from many research sources that track media buying trends, advertising and other revenue indicators, Twitter usages statistics from research firms and user surveys and interviews with executives at ad agencies, brands, online ad publishers and other industry leaders".

eMarketer's anticipated 2012 revenue for Twitter remains unchanged at $288.3m, with 90 per cent of that coming from the US. ®